Springboot POI导出Excel Springboot POI导出Excel（浏览器）

//Controller
@RequestMapping("/stateExport")
  public void stateExport(HttpServletResponse response,@RequestParam("deviceId") Long deviceId, String startTime,String endTime) {
    try {
      deviceMonitorService.stateExport(response, deviceId, startTime,endTime);
      LOG.info("导出成功");
    } catch (Exception e) {
      LOG.error("导出异常:",e.getMessage());
    }
  }

//Service
  @Override
  public void stateExport(HttpServletResponse response, Long deviceId, String startTime, String endTime) throws Exception{
   //list自己查询得出
    List<StateDetailsResult> list = queryStateDetails(deviceId, startTime, endTime);
    String time = TimeUtils.YEAR_DAY_SECOND_FORMAT.format(new Date());
    //sheet名称
    String sheetName = deviceDtls.getName() + "状态"+time;
    //文件名称
    String excelName = deviceDtls.getName() + "状态"+time+".xlsx";
    //文件头
    String[] strings = {"状态名称","开始时间","结束时间","状态时长"};
    String path = this.getClass().getResource("").getPath() + "excel";
    DownloadFileUtil.createDirs(path);
    String filePath = path + "/" + sheetName + ".xls";
    stateCreateExcel(list,strings,sheetName,excelName,filePath);
    DownloadFileUtil.download(filePath, response);
  }

public String stateCreateExcel(List<StateDetailsResult> list, String[] strArray,String sheetName,String excelName,String filePath)throws Exception {
    // 总数据条数
    int dataSize = list.size();
    // 线程数
    int threadNum = 2;
    int threadSize = dataSize / threadNum;
    ExecutorService exec = Executors.newFixedThreadPool(threadNum);
    //cutList 和输入list类型保持一致
    List<StateDetailsResult> cutList = null;

    // 第一步，创建一个webbook，对应一个Excel文件
    XSSFWorkbook wb = new XSSFWorkbook();
    // 第二步，在webbook中添加一个sheet,对应Excel文件中的sheet
    XSSFSheet sheet = wb.createSheet(sheetName);
    sheet.setDefaultColumnWidth(20);// 默认列宽
    // 第三步，在sheet中添加表头第0行,注意老版本poi对Excel的行数列数有限制short
    XSSFRow row = sheet.createRow((int) 0);
    // 第四步，创建单元格，并设置值表头 设置表头居中
    XSSFCellStyle style = wb.createCellStyle();
    // 创建一个居中格式
    style.setAlignment(HSSFCellStyle.ALIGN_CENTER);

    // 添加excel title
    XSSFCell cell = null;
    for (int i = 0; i < strArray.length; i++) {
      cell = row.createCell((short) i);
      cell.setCellValue(strArray[i]);
      cell.setCellStyle(style);
    }
    List<Callable<Integer>> tasks = new ArrayList<Callable<Integer>>();
    Callable<Integer> task = null;
    // 第五步，写入实体数据 实际应用中这些数据从数据库得到,list中字符串的顺序必须和数组strArray中的顺序一致
    int startNum ;
    System.out.println("任务开始,总数："+list.size());
    // 开始时间
    long start = System.currentTimeMillis();
    System.out.println("线程任务执行");
    for (int i = 0; i < threadNum; i++) {
      startNum = threadSize * i;
      if (i == threadNum - 1) {
        cutList = list.subList(threadSize * i, dataSize);
      } else {
        cutList = list.subList(threadSize * i, threadSize * (i + 1));
      }
      //listStr 和输入list类型保持一致
      final List<StateDetailsResult> listStr = cutList;
      int finalStartNum = startNum;
      task = new Callable<Integer>() {
        final int s= finalStartNum;
        @Override
        public Integer call() throws Exception {
          for(int j=0;j<listStr.size();j++){
            XSSFRow row =getRow(sheet,s+j);
            //设置每一列展示内容自己设置
            row.createCell(0).setCellValue(listStr.get(j).getName());
            row.createCell(1).setCellValue(listStr.get(j).getStartDateTime());
            row.createCell(2).setCellValue(listStr.get(j).getEndDateTime());
            row.createCell(3).setCellValue(listStr.get(j).getDateTime());
          }
          return 1;
        }
      };
      // 这里提交的任务容器列表和返回的Future列表存在顺序对应的关系
      tasks.add(task);
    }
    try {
      List<Future<Integer>> results = exec.invokeAll(tasks);
    } catch (Exception e) {
      e.printStackTrace();
    }
    // 关闭线程池
    exec.shutdown();
    DownloadFileUtil.delfile(filePath);
    // 第六步，将文件存到指定位置
    try {
      FileOutputStream fout = new FileOutputStream(filePath);
      wb.write(fout);
      fout.flush();
      fout.close();
    } catch (Exception e) {
      e.printStackTrace();
    }
    System.out.println("线程任务执行结束");
    System.err.println("执行任务消耗了 ：" + (System.currentTimeMillis() - start) + "毫秒");
    return filePath;
  }

//线程同步，保证不会多插入数据
private synchronized XSSFRow getRow(XSSFSheet sheet, int rownum) {
 //如果不包含列头，+1去掉即可
    return sheet.createRow(rownum+1);
  }

package com.sec.deviceband.utils;

import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.net.URLEncoder;

public class DownloadFileUtil {
 
 /**
 * 判断路径是否存在不存在则创建
 * @param path
 */
 public static void createDirs(String path) {
 File file = new File(path);
 if (!file.exists()) {
  file.mkdirs();
 }
 }
 /**
 * 下载
 * 
 * @param path
 * @param response
 */
 public static void download(String path, HttpServletResponse response) {
 try {
  // path是指欲下载的文件的路径。
  File file = new File(path);
  // 取得文件名。
  String filename = file.getName();
  // 以流的形式下载文件。
  InputStream fis = new BufferedInputStream(new FileInputStream(path));
  byte[] buffer = new byte[fis.available()];
  fis.read(buffer);
  fis.close();
  // 清空response
  response.reset();
  // 设置response的Header
  response.addHeader("Content-Disposition", "attachment;filename="
   + URLEncoder.encode(filename, "utf-8"));
  response.addHeader("Content-Length", "" + file.length());
  OutputStream toClient = new BufferedOutputStream(
   response.getOutputStream());
  response.setContentType("application/vnd.ms-excel;charset=utf-8");
  toClient.write(buffer);
  toClient.flush();
  toClient.close();
  delfile(path);
 } catch (IOException ex) {
  ex.printStackTrace();
 }
 }
 
 /**
 * 判断文件是否存在则删除
 * 
 * @param filepath
 */
 public static void delfile(String filepath) {
 File file = new File(filepath);
 if (file.exists()) {
  file.delete();
 }
 }
}